Colored adhesive tape



June 19, 1956 w. c. EATON COLORED ADHESIVE TAPE Filed April 29, 1955COLORED ADHESIVE TAPE Wentworth C. Eaton, Rochester, N. Y., assgnor toEastman Kodak Company, Rochester, N. Y., a corporation of New JerseyApplication April 29, 1953, Serial No. 351,849

4 Claims. (Cl. 8-18) This invention relates to a light-sealing adhesivetape. More particularly this invention concerns an improvedlight-sealing adhesive tape which is particularly adapted for uses inthe photographic industry.

In the art there are many instances where there is a need for anadhesive tape having the property of being capable of not only joiningparts together but to form a relatively light-tight joint. This need isencountered frequently in the photographic industry. That is, forexample, in sealing packages containing light-sensitive photo` graphicmaterials it is, of course, important that the seal be sufficientlylight-tight that any light leakage be well below that which would causefogging of the photographic materials. It will also be noted that theaccomplishment of such light-tight seals should be with materials whichwould not chemically or otherwise exert an injurious effect on thesensitive photographic contents.

It has been customary in the prior art to prepare such type tape byrather heavily impregnating or loading the tape with dark coloredpigments. For example, the use of rather substantial quantities ofgraphite in the production of such type tape has been resorted to. Whilethe resultant prior art tape has merit from the standpoint of giving arelatively light-proof sealing, there have been cer tain disadvantagesin such prior art tape. For example, tape containing or associated witha high content of a dark pigment may be of such an overall dark colorthat it presents an unpleasing appearance. Furthermore, because of thedark color of such tape it is either impossible to place readily visiblemarkings upon the tape, or if an attempt is made to mark it, here againrelatively unsatisfactory results have been obtained.

It is therefore apparent that providing an improved light-proof tapewhich is of pleasing appearance and which is receptive to clear visiblemarking, represents a highly desirable result. After extensiveinvestigation I have found how such improved tape may be prepared in aneconomical manner, lending itself to large scale manufacture.

This invention has for one object to provide an improved relativelylight-impermeable adhesive tape. A special object is to provide alight-impermeable tape of the class mentioned, which is especiallyadapted for uses in the photographic industry. A still further object isto provide a relatively light-impermeable tape which is especiallyadapted for sealing seams of various types of containers where -it isdesired to prevent the penetration of light to the interior of saidcontainers. Another object is to provide a tape of the class indicatedwhich is not only more pleasing in appearance, but which may be printedupon or otherwise marked with the result that said markings are moreclearly and readily observable. Still another object is to provide amethod for the manufacture of the improved tape referred to herein.Other objects will appear hereinafter.

In the broader aspects of my invention I have found that a light-coloredfabric base may be first coated with a light-colored adhesive. Thelight-colored adhesive is then damage thereto.

2,751,276 Patented June 19, 1956 overcoated with a dark, such as ablack, adhesive coating composition. By this combination thelight-sealing qualities of the adhesive tape appear to be maintained.However, the fabric side of the tape, namely the side away from thedark-colored adhesive, still maintains its light color, hence morereadily Visible and pleasing appearance.

' industry, the fabric tape is of a light color, colored by certaincoloring materials which are noninjurious photographically. Thelight-colored fabric foundation is then coated with a white adhesive ofa special composition which will be described in detail hereinafter.This white adhesive is then overcoated with a black adhesive compositionof a special formulation as will also be described in detailhereinafter.

The foregoing describes the generic aspects of my invention. However, ifdesired, the printed fabric portion may be overcoated with a lacquerglaze or other type of textile nish. Also as desired, the adhesivesurface of my tape may be overcoated with a thin protective tissue mediaor coating for temporarily covering the adhesive prior to use. Suchcoatings may be detachable to expose the adhesive or may be of suchminute thinness that upon the application of pressure they merge intothe adhesive permitting the adhesive to function. However my tape asgenerically described is sutliciently stable that the adhesive side maybe rolled up against the fabric side without In other words, my adhesivecombination is of such a character that the dark coloring therein doesnot migrate into the fabric either when in direct contact therewith orby migrating through the intermediate light-colored adhesive layer.

As respects the fabric base material, while various commerciallyobtainable cloths may be employed, I have found that a materialdescribed as thin lawn cloth is quite satisfactory. This material is ofan approximate construction of 96 x 100 ends and picks per inch and aweight of 7 yards per pound.

For a further understanding of the instant invention reference will bemade to the attached drawing. Fig. l is a diagrammatic side elevationview of apparatus arrangements such as might be used in manufacturinglight-impermeable tapes in accordance with the present invention.

Fig. 2 is a diagrammatic representation on an exaggerated scale of across section of the tape of the present invention.

Refering tor Fig. l (A), 2 represents a roll of the fabric which is tobe converted into the fabric tape of the present invention. For example,this roll might be comprised of the lawn cloth referred to above. Thefabric is unrolled and guided through the equipment by virtue of driveor guide rolls such as 3. The mangles 4, and pick-up roll 5 may beemployed to motivate the fabric base through the equipment. In thepassage of the fabric through the process it passes through dye orcoloring tanks 6 and 7 where it is colored, then through mangles 4 tosqueeze out surplus liquid, then over dryer drums 3 where remainingliquid is removed and finally wound up on 5.

Referring further to Fig. 1 and now to (B), the colored cloth on 5 istransferred to roll 12. The raw fabric passes by means of suction drive13, consisting of a series of small driven rolls forming the top of asuction box which hold the material tightly against the rolls and thedriven rolls pull the material away from the stock roll, in the vicinityof a hopper 16 or other equivalent device for applying the firstadhesive layer, namely the layer of the light-colored adhesive. Thepreliminarily coated fabric then passes through suitable drying orsolvent removing device 17. In this device the adhesive is caused to setup to some extent. However complete curing of the adhesive at this stateis not necessary. Upon emerging from the dryer the preliminarily coatedfabric passes in the vicinity of a second coating device 18, from whichis applied the layer of dark-colored adhesive. Suitable smoothing meanssuch as doctor blades, leveling knives or the like (not shown) of coursecan be included in the equipment for controlling the accuracy of thecoating. Likewise in place of coating hoppers, coating rolls or the likemay be used.

After the coating from device 18 is applied, the'fabric tape then passesinto a second dryer 19 where suicient curing takes place to removea'substantial portion of the solvent or other similar volatiles from theadhesive to form the finished tape. l

Other operations, such as preliminary slitting and the like, may beaccomplished by suitable equipment, generally indicated at 20. Thefinished tape is wound up on rolls 23 and 24.

Referring now to Fig. 1 (C), the rolls from Z3 or 24 are mounted at 25and fed through a printer 26 from which it then passes to any furthertreatment, such as overcoating with a lacquer, further slitting, etc.

Referring to Fig. 2, it will be observed that my tape is made up of thefabric or foundation layer 31, such as a layer of lawn cloth referred toabove. This cloth in accordance with my preferred embodiment may becolored with certain dyes which do not exhibit an adverse photographiceffect. A description of certain of these dyes will be set forthhereinafter. 32 represents the layer of light-colored adhesive. 33represents the layer of dark-colored adhesive. The entire combinationgives an excellent flexible, light-impermeable tape which has a pleasingappearance and is readily receptive to marking or printing withconventional inks and marking devices.

A more complete understanding of my invention, and t particularly thepreferred embodiment thereof, will be had from a consideration of thefollowing specific examples. It is to be understood that these specificexamples concern a light-impermeable tape very suitable for use in thephotographic industry. However, it is to be further understood that mytape has other uses and that the following speciiic examples areprimarily for the purpose of illustration.

Example I ln accordance with this example, the fabric used was a lightlawn cloth as above mentioned. Its approximate construction was about100 ends and picks per inch and the weight was 7 yards per pound. Thefabric was coated in an apparatus as shown in Fig. l. That is, the firstcoating applied from hopper 16 comprising white adhesive of thefollowing composition:

Antioxidant r4 A portion of the benzene solvent was evaporated from thetirst coating. Then the black adhesive from hopper 18 was applied overthe first-mentioned adhesive. This adhesive was of the followingcomposition:

Natural rubber 7.50 Rosin 7.00 Lanolin 1.50 Graphite 1.00 Barytes 5.00Benzene 77.50 Antioxidant .50

Example II In accordance with this Example a tape especially useful forphotographic purposes was prepared. In this example the fabric used wasof the same general weight and construction as the fabric of Example I.However, in this Example the fabric was colored with a yellow dye in 6and 7. The dye used was Pontamine Yellow SXPE. This is a dye of thefollowing general composition:

SOaNa Naoah dosNa The yellow dye is the sodium salt of dinitro azodistilbene tetra sulfonic acid, Inex No. 622.

It has been found that fabric thus colored does not exert an adversephotographic effect. In place of the dye just mentioned, it is possibleto use Amanil Chrysophenine G. This latter dye has the following generalcomposition:

NaOsS This is para-ethoxydiazobenzene stilbene disulphonate- Index No.365, Schultz Index No. 726.

The yellow'fabric just described was then overcoated first with a whiteadhesive generally in accordance with the white adhesive used in ExampleI. The first adhesive coated was then further overcoated with the blackadhesive of Example I. The finished tape was cured and wound up. Thisparticular yellow tape was printed in red type with excellent results.in addition, the lightimpermeability of this type was most excellent.This may be due to some extent to the black and yellow dye combinationof the tape as well as to the fact that the intervening white layer alsoexhibits some deterrence to light passage.

tially-the same as that described under Example Il, is used. However,the white adhesive used in this example is termed mixed white, and hasthe following composition: (approximate percentages by weight) GRS-80synethetic rubber 8.00 Piccolyte resin 6.00 Titanium oxide 4.00 Barytes2.00 Lanolin 1.50 Benzene 78.00 Antioxidant .50

The tape was overcoated with a black adhesive as already described inthe other examples. Likewise, in this Example the finished tapeexhibited an excellent appearance as well as good light-impermeabilityand capability of sealing package joints.

While the foregoing examples are illustrative of my preferredembodiments, certain changes may be made in my invention. For example,it is possible to incorporate suitable yellow coloring in the whiteadhesive composition, particularly where this light-colored compositionis to be applied to a yellow facbric. However, the white adhesive doesbrighten the yellow fabric to some extent. Also, in the manufacture oftape for uses such as the sealing of food containers against lightpeneration or other uses where the problems of a photographic damage andthe like may not be present, it may be possible to uitilize differentadhesive compositions than those set forth above. That is, in someinstances a carbon black-containing black adhesive may be employed.However, the graphite-containing adhesive specified above is regarded asmuch superior. Likewise, in place of the natural rubber in someinstances it may be possible to use synthetic rubber or mixtures ofnatural and snythetic rubber.

The proportions may be varied several percent each way from the valuegiven. That is, considering the rubber content of 8%, for example, thismay vary from 4% to The solvent may vary from 60-80%, the pigment from5% to 20%. In still further detail, the amount of rosin may vary between3 to 12%, lanolin .5 to 3%, zinc oxide 2 to 6%, barytes 1 to 10%,antioxidant .25 to 2%, and graphite ylo to 4%.

In place of the pigments and certain other ingredients given in thepreferred embodiment, the following may be used. Various mixtures ofTiOz and BaSO4 and a lead salt from the group consisting of PbCrO4 andPbCr2O:. Other resins such as Piccolyte,1 Staybelite,2 and coumarineindene resins.

As antioxidant I may use aldol alpha-naphthylamine, phenylbeta-naphthylamine, or p-(p-to1ylsulfonylamido)- dipheulamine.

As indicated above, the tapes in accordance with the 1 Terpene resin.

2 Hydrogenated rosin.

195(lmdbook of Material Trade Names, Zimmerman & Lavine,

present invention may be used for any of the various uses for whichsimilar tapes have been utilized. In addition they are especiallyvaluable for use where it is desired to print or mark upon the tape insome manner.

I claim:

l. A tape consisting essentially of light colored cloth, one surfaceonly being coated with pigmented light colored adhesive, said lightcolored adhesive being further coated with a black pressure-sensitiveadhesive pigmented with graphite, said tape being light impermeable andcapable of taking printing ink on the nonadhesive coated side.

2. A tape consisting essentially of a light colored lawn cloth, onesurface only being coated with a pigmented light colored adhesive, saidlight colored adhesive having the following composition (percentages byweight), natural rubber 4--l6, rosin 3-12, lanolin .543, zinc oxide 246,barytes l-5, benzene -80, antioxidant .25-2, said light colored adhesivebeing further coated with a black pressure-sensitive adhesive, saidblack adhesive having the following composition: (percentages by weight)natural rubber 4-16, rosin 3-12, lanolin .5-3, graphite .5-4, barytes3-10, solvent 60-80, antioxidant .252, whereby a light impermeableadhesive tape is obtained which has a pleasing appearance and is capableof receiving ordinary ink printing on the light colored cloth surfacethereof.

3. A tape consisting essentially of light colored cloth, one surfaceonly being coated with pigmented llight colored adhesive, said pigmentbeing from the group consisting of PbCrO4 and PbCrzOv, said lightcolored adhesive being further coated with a black pressure-sensitiveadhesive pigmented with graphite, said black adhesive also containingrubber, rosin, and barytes, said tape being light impermeable andcapable of taking printing ink on the nonadhesive coated side.

4. A tape consisting essentially of light colored cloth which cloth iscolored with a yellow dye from the group consisting of Pontarnine YellowSXPE and Amanil Chrysophenine G, one surface only of the cloth beingcoated with a pigmented light colored adhesive, said light coloredadhesive containing natural rubber', rosin, lanolin, zinc oxide andbarytes, said light colored adhesive being further coated with a blackpressure-sensitive adhesive pigmented with graphite, said black adhesivein addition to the graphite also containing natural rubber, rosin,lanolin, barytes, said tape being light impermeable and capable oftaking printing ink on the nonadhesive side.

References Cited in the le of this patent UNITED STATES PATENTS2,236,567 Drew Apr. 1, 1941 2,352,463 Wenzelberger .Tune 27, 19442,355,632 Coffey Aug. 15, 1944 2,555,745 Hopkins June 5, 1951

1. A TAPE CONSISTING ESSENTIALLY OF LIGHT COLORED CLOTH, ONE SURFACEONLY BEING COATED WITH PIGMENTED LIGHT COLORED ADHESIVE, SAID LIGHTCOLORED ADHESIVE BEING FURTHER COATED WITH A BLACK PRESSURE-SENSITIVEADHESIVE PIGMENTED WITH GRAPHITE, SAID TAPE BEING LIGHT IMPERMEABLE ANDCAPABLE OF TAKING PRINTING INK ON THE NONADHESIVE COATED SIDE.